Top: section of the FUSE observation showing the necessity of a detailed modeling of the ISM. The dashed line is the final, pure photospheric model. The full (red) line shows a combined stellar and interstellar model. Blue marks at the bottom denote interstellar H₂ absorption lines. Bottom: comparison of (pure photospheric) TMAP models with log g = 7.2 (thick, black) and log g = 7.7 (thin, red), normalized to the flux of the log g = 7.2 model at 999 Å for comparison. The full lines are calculated with the determined reddening of (Sect. 2.1), the dashed lines (shifted in log f_λ by  − 0.4 for clarity) with .